s = "console.log('hello world')";
eval(s);   // 字符串

// https://tools.jb51.net/password/evalencode
// eval("xx")     =>  "xx"  一定是字符串
eval(
    function (p, a, c, k, e, d) {
        e = function (c) {
            return (c < a ? '' : e(parseInt(c / a))) + ((c = c % a) > 35 ? String.fromCharCode(c + 29) : c.toString(36))
        };
        if (!''.replace(/^/, String)) {
            while (c--) d[e(c)] = k[c] || e(c);
            k = [function (e) {
                return d[e]
            }];
            e = function () {
                return '\\w+'
            };
            c = 1
        }
        ;
        while (c--) if (k[c]) p = p.replace(new RegExp('\\b' + e(c) + '\\b', 'g'), k[c]);
        return p
    }('0.2("1 3")', 62, 4, 'console|hello|log|world'.split('|'), 0, {}))